The quilt patch titled
Subject: zram: permit reclaim in zstd custom allocator
has been removed from the -mm tree. Its filename was
zram-permit-reclaim-in-zstd-custom-allocator.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Subject: zram: permit reclaim in zstd custom allocator
Date: Mon, 3 Mar 2025 11:03:25 +0900
When configured with pre-trained compression/decompression dictionary
support, zstd requires custom memory allocator, which it calls internally
from compression()/decompression() routines. That means allocation from
atomic context (either under entry spin-lock, or per-CPU local-lock or
both). Now, with non-atomic zram read()/write(), those limitations are
relaxed and we can allow direct and indirect reclaim.
Link: https://lkml.kernel.org/r/20250303022425.285971-17-senozhatsky@xxxxxxxxxxxx
Signed-off-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Hillf Danton <hdanton@xxxxxxxx>
Cc: Kairui Song <ryncsn@xxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Yosry Ahmed <yosry.ahmed@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/backend_zstd.c | 11 +----------
1 file changed, 1 insertion(+), 10 deletions(-)
--- a/drivers/block/zram/backend_zstd.c~zram-permit-reclaim-in-zstd-custom-allocator
+++ a/drivers/block/zram/backend_zstd.c
@@ -24,19 +24,10 @@ struct zstd_params {
/*
* For C/D dictionaries we need to provide zstd with zstd_custom_mem,
* which zstd uses internally to allocate/free memory when needed.
- *
- * This means that allocator.customAlloc() can be called from zcomp_compress()
- * under local-lock (per-CPU compression stream), in which case we must use
- * GFP_ATOMIC.
- *
- * Another complication here is that we can be configured as a swap device.
*/
static void *zstd_custom_alloc(void *opaque, size_t size)
{
- if (!preemptible())
- return kvzalloc(size, GFP_ATOMIC);
-
- return kvzalloc(size, __GFP_KSWAPD_RECLAIM | __GFP_NOWARN);
+ return kvzalloc(size, GFP_NOIO | __GFP_NOWARN);
}
static void zstd_custom_free(void *opaque, void *address)
_
Patches currently in -mm which might be from senozhatsky@xxxxxxxxxxxx are
